Grinding mill



July 7, 1931. v. SAHMEL 1,313,086

GRINDING MILL Filed Nov. 14. 1929 2 Sheets-Sheet 1 X INVENTOR July 7, 1931. v, SAHME'L 1,813,086

GRINDING MILL Filed Nov. 14. 1929 2 Sheets-Shee 2 5g lNVjNTOR IWM MW Patented July 7, 1931 UNITED STATES PATIENT OFFICE VIGGO SAHMEL, OF FOREST HTLLS, NEW YORK, ASS IGNOB TO I. I. SMID'IH & 00., 01' NEW YORK, N. Y., A CORPORATION OF NEW JERSEY enmnme MILL Application filed November 14, 1929. Serial No. 407,06 3.

In the manufacture of Portland cement the importance of preventing, during the grinding of the cement materials, such a rise of temperature within the grinding mill as would bring about a change of the gypsum content to plaster of Paris, with consequent undesirable effect upon the uality of the cement, has come to e genera ly recognized. Various'efi'orts have been made to prevent the heating of the mill and the material therein incident to the grinding, as by the introduction of an evaporable substance or by the circulation of a cooling medium, such as water, through a jacket without the mill, or by the provision of heat transferring devices within the mill. however, have been dependent upon observation and manual regulation, not only re-. 'uiring constant watchfulness on the part of an attendant, but introducing the uncertain element of human control and inevitably lacking in that degree of exactness of regulation which is essential to satisfactory and economic o eration, which requires the temperature wit in the mill to be near the critical temperature which would effect a change of gypsum to plaster of Paris without exceeding it. It has been the object of the present invention to provide means whereby the desired temperature within a grinding mill may be maintained automatically. In the present embodiment of theinvention, chosen for illustration and explanation of its nature, a cooling medium, such as water, is supplied to the acket or chamber about the mill and devices are rovided whereby the circulation of the coo ing medium is controlled automatically. The invention will be more fully explained hereinafter with reference to the accompanying drawings in which it is illustrated, and in which:

Figure 1 is a view in longitudinal, sectional elevation, partly in outline, of a grinding mill equipped with devices for controlling automatically the circulation of the cooling medium in the chamber about the mill.

- Figure 2 is a detail view, in sectional elevation, of a thermostatically controlled All of such devices,

valve for controlling the flow of the cooling medium. I v

Figure 3 is a detail view, in sectional ele vation, of a dial-type thermometer interconnected with an alarm.

Figure 4 is a detail view, in sectional elevation, of a magnetically operated valve interconnected with a motor for driving the mill, the mill and the motor with their associated parts being indicated in outline and on a smaller scale than that on which the valve is shown. i

The mill which may be and is represented as of conventional type, has at one end an inlet 2 for the material to be ground and at 3 an outlet for the ground material. The mill is shown more particularly in Figure 4 as having a driving gear 4 engaged by a pinion 5 of a motor 6. In the construction shown the shell of the rotating mill 1 is encircled by a casing 7 which is stationa and is supported independently of the mi 1 by means unnecessary to be shown. Within the casin 7, at the top, is aseries of spray pipes 8 w ich may be supplied with water or 0 er cooling medium through pipes 9 and 9, flow indicators 40 and valves 41 being preferably provided in the connections between the pipe 9 and the spray pipes 8. in its lower part the casing 7 is provided with outlets 10 connected to a common drain pipe 11.- The cooling medium may be supplied through the pipes 9 from any conof the valve 14, is extended upward within a chamber 16 and is connected to a sylphon 17, or pressure-sensitive bellows, which is connected through a pipe 18 with a thermostatic bulb 19 located, as shown in Figure 1,

- dependent means b at the outlet end of the mill. The bulb 19, the ipe 18 and the sylphon 17 may be fille or artially filled with a fluid readily expansib 0 under the influence of heat so that when the temperature at the outlet of the mill rises above the predetermined degree the sylphon will be expanded and the valve 14 be moved to permit a freerflow of cooling medium through the supply pipe. On the other hand, if the temperature at the outlet of the mill falls below the predetermined de 'ree the sylphon will contract and the flow o cooling medium through the pipe will be reduced until such time as the tem erature in the mill is restored to the I pre etermined degree.

By observation of the flow indicators 40 the mill attendant will be informed as to the circulation of the cooling medium and the proper distribution of the cooling medium in different parts of the casing 7 can be assured by main ulation of the valves 41.

In the event of ailure of the valve 12 to function properly there is provided an inwhich an undesirable condition in the mil will be signalled and the attention of the operator or attendant called to that fact. As shown, such means may comprise a thermostaticall controlled dial-t pe thermometer, the relation of which is in icated at 20 in Figure 1, while the details of construction are shown more particularly in Figure 3. A bulb 21,-located at the outlet of the mill, as shown in Figure 1, is connected by a tube 22 with a sylphon 23, shown in Figure 3. The movable memher of the sylphon is operatively connected with a lever 24 to which is connected a pointer or indicator 25 which moves over a scale 30. The indicator is electrically connected through the s lphon 23 and housing 28 with one leg 25 oi an electric circuit an carries, on opposite sides, contacts 26 which are adapted to make contact, as the indicator reaches the limit of its motion in either direction, with one or the other of insulated contacts 27 which are connected to the other leg 27 of the circuit. Included in one branch of the electric circuit, as in the branch 25 is a horn or signal 32, so that when the temperature in the mill varies materially from the desired temperature, in either direction, that fact will be indicated by the signal and the attention of the operator' attracted so that the difiiculty may be remedied.

It is also desirable to provide means whereby the flow of cooling medium shall be started automatically when the mill motor is started and shall be stopped automatically when the mill motor is stopped, either through failure or intentionally. There is therefore provided a magnetically controlled shut-oif valve connected into the supply pipe line, as shown in Figures 1 and 4, and con- 39, the coil 36 causes the core 37 to move in such a direction as to move the valve 35 from its seat in the box 34 against the pressure of the spring 38 and thereby permit the cooling medium to flow through the pipe line. If the supply of current to the motor ceases, either through failure or through the opening of the circuit in the starter box 39, the coil 36 is at the same time deprived of current and, by the action of the spring 38, the valve 35 is moved to shut off the flow of cooling medium through the pipe line.

While certain specific constructions of the devices for controlling the flow of the cool ing medium and for signalling any material variation of temperature in the mill have been shown and described herein, it will be seen that the construction and arrangement of such devices may be changed to suit different conditions of use and that, except as subject to the temperature of the material acted upon.

2. The combination with a grinding mill and means to supply a cooling medium for the purpose of'preventing an undesirable increase of temperature in the mill, of a valve to control the flow of'the cooling medium, and thermostatically controlled devices to regulate'the operation of said valve and subect to the temperature of the material acted upon.

3. The combination with a grinding mill and means to supply a cooling medium for the purpose of preventing an undesirable increase of temperature in the mill, of means to control the flow of the cooling medium, a sylphon operatively connected to said means, and a thermostatic bulb located in the mill and subject to the temperature of the material acted upon and operatively connectul' to the lphon.

4. he combination with a grinding mill,

a motor therefor, and means to supply a 5 cooling medium for the purpose of preventing an undesirable increase of temperature in the mill, of means to control the flow of the cooling medium, devices to actuate said means, and electric connections between the motor and said means whereby the operation of said means is dependentupon the operation of the motor. 5. The combination with a grinding mill, a motor therefor, and means to supply a cooling medium for the purpose of preventing an undesirable increase of temperature in the mill, of a valve to control the flow of the cooling medium, electro-ma etic devices to actuate said valve, an electrical a connections'between themotor and. said devices whereby the operation of said devices is dependent upon the operation of the motor.

6. The combination with a 'grinding mill, a motor therefor, and means to supply a cooling medium for the purpose of preventing an undesirable increase of temperature in the mill, of a valve to control the. flow of the cooling medium, an armature connected'to said valve, an electro-magnetic coil for cooperation with the armature, electrical connections between the motor and said coil, and a spring opposing the action of the coil on the armature and the valve. This-specification signed this 13th day .of

November, A. D. 1929. 

